Electrically erasable reference cell for accurately determining threshold voltage of a non-volatile memory at a plurality of threshold voltage levels
US5774395A · kind A · utility
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Key dates
| Filing date | Nov 27, 1996 |
| Grant date | Jun 30, 1998 |
| Priority date | — |
| Expiry date | Nov 27, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C2211/5634
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A reference cell in a nonvolatile memory is electrically erasable and the electrically erasable character of the memory is exploited to expand the voltage range over which a differential amplifier is useful for sensing the state of a bit. Selected elements of a reference cell are electrically erased and reprogrammed for accurately tuning the sensing of multiple data states in a memory cell. For example, 64 or more data states may be tuned so that a single megabyte of memory is allocated to store six megabytes of information.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.